[db] integrate the values for italic angle and weight into style choice
[tool] remove obsolete source documentation
[db] do not rely on italic angle when determining the font style

The italic angle will be non-zero for semibold and other variants which
messes up the assignment of font families.
[parsers] fix incomplete feature separator rule
Merge pull request #183 from phi-gamma/texlive2014

improve detection of bold fonts